Man-machine interface for controlling access to electronic devices

ABSTRACT

The invention disclosed herein describes a man-machine interface device for controlling access to electronic devices. The man-machine interface device comprises an electronic display unit including a transparent finger touch sensor region that is seated above the display apparatus, which is responsible for determining the presence and absence of a finger and for generating fingerprint images when a finger is detected. The man-machine interface device also includes a controller unit that is coupled to the display apparatus, the finger touch sensor region, and at least one electronic device. The method of the invention describes a process for authenticating individuals and verifying their security privileges to access sensitive data, based on a finger-touch selection of an icon presented on the display apparatus of the man-machine interface device.

RELATED U.S. APPLICATION DATA

This application claims priority to and is a continuation of U.S. patentapplication Ser. No. 12/201,568, entitled “Man-Machine Interface ForControlling Access To Electronic Devices”, filed Aug. 29, 2008, now U.S.Pat. No. 7,525,537; which is a continuation of U.S. patent applicationSer. No. 10/997,291, entitled “Man-Machine Interface For ControllingAccess To Electronic Devices”, filed Nov. 24, 2004, now U.S. Pat. No.7,420,546; which is a divisional of U.S. patent application Ser. No.10/858,290, entitled “Man-Machine Interface For Controlling Access ToElectronic Devices”, filed Jun. 1, 2004, now abandoned; which claimspriority to U.S. Patent Application No. 60/474,750 entitled, “SecureBiometric Identification Devices and Systems for Various Applications,”filed May 30, 2003; each of which is hereby incorporated by reference intheir entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to the field of electronic device userinterfaces and authorization techniques, and more specifically to thefield of fingerprint imaging sensors and touch screen displayapparatuses.

2. Necessity of the Invention

Modern electronic devices have developed a myriad of functionalities andassociated user interfaces. Many electronic devices use a displayscreen, such as a monitor or display apparatus, to provide feedback tothe user. Handheld devices, such as the personal digital assistant andthe cell phone, have an important user interface constraint—form factor.In both devices, manufacturers desire to minimize the size and weight ofthe device; as one means to accomplish this, the display is small andbuttons are placed close together.

In recent years, manufacturers of many electronic devices havesubstituted touch screen technology for the traditional display. Touchscreens have the same appearance and style of a traditional screen, buthave the added ability to determine the location of applied pressure.This allows individuals to use a stylus in a similar manner as a personuses a mouse to point to icons on a monitor—the individual may touch thescreen at the location of a particular icon. Software running on thedevice determines the location of the touch and determines theassociated software function, such as opening an address book. Becausethe additional button control interface can be eliminated, manufacturerscan make the display larger and simpler to use.

As the functionality of electronic devices expands, individuals may wishto protect certain data stored within the device. For example, the ownerof a personal digital assistant may choose to use his PDA to send andreceive private e-mail. If the data is particularly sensitive, a simplepassword or PIN combination may not be considered adequate security andthe individual may desire to use biometric authentication on the device.The most common form of biometric authentication, fingerprint scanning,requires a hardware module that is typically the size of a postagestamp. On a device where size and weight are limited, the addition ofthis module can be costly.

Digital Fingerprint Capture Technologies

There are three common types of fingerprint capture technologies:optical, capacitive, and ultrasonic. Each of the three technologiescombines its associated hardware capture mechanism, which varies fromtype to type, and typically a software or firmware controller. Thiscontroller is often responsible for analyzing the captured image,extracting minutia points, and creating a final template. Minutiae arepoints that represent all of the unique characteristics of afingerprint—one example is the location of an intersection of ridges orvalleys in the print. A template is typically composed of thirtyminutiae and can be used to uniquely identify a fingerprint. This allowsthe scanner or other storage device to store only the requisite datapoints without storing the entire image.

Of the three types of fingerprint capture technologies, optical scannersare the oldest and most common, and they are composed of a glass orplastic plate with a light source and a charge coupled device (CCD)beneath. The light source is typically an array of light emitting diodes(LEDs), and the CCD is an array of light-sensitive diodes. When thefinger is placed on top of the plate, the LEDs illuminate the finger andeach diode of the CCD records the light that touched it, creating animage in which the ridges are dark and the valleys are light. Opticalscanners are fairly resistant to temperature fluctuations, and canprovide an image quality of approximately 500 dots per inch (dpi). Onemajor concern of this technology is that latent prints—“left over”fingerprints on the plate—can cause a superpositioning effect and createerror. Additionally, these types of scanners are susceptible to “gummibear attacks”, in which a fingerprint is lifted from a glass or otherobject, placed on a pliable and sticky material, such as a gummi bear,and can provide a false acceptance. One other point of note is that theplate must be quite large; this creates ease of use but may takeunavailable real estate on a board.

Capacitive sensors are much newer than optical scanners, and arecomposed of an array of cells; each cell has two adjacent conductorplates, which are embedded within an insulating layer. The insulatinglayer is typically a glass plate. When the finger is placed on top ofthe insulating layer, it creates a subsequent electric field between thefinger and the conductor plates, creating capacitance. Because thesurface of a finger is a succession of ridges and valleys, the electricfield varies over the face of the finger as the distance from the plateto the finger varies. The capacitance or voltage may be determined fromthe electric field, and is commonly translated into an 8-bit grayscaleimage with approximately 200 to 300 grid points in both the x- andy-plane. This creates more detailed data than the optical sensor.Capacitive scanners are typically smaller than optical sensors becausethe cells are composed of semiconductor devices, rather than a CCD unit.

While capacitive scanners are cheaper and smaller than optical sensors,their durability is unknown due to their short time in use, and thesmall size can make it more difficult for an individual to enroll andauthenticate properly. Most fingerprint sensors use direct current (DC)coupling, although a few companies are beginning to use alternatingcurrent (AC) coupling to penetrate to the live layer of the skin.Because the capacitive scanner is dependent on the electric field andcapacitance between a finger and the glass plate, the scanner cannot befooled by the “gummi bear attack” as described above; the dielectricconstant for the finger is much different from a gummi bear, and so thecapacitance will vary significantly.

The most accurate but least common finger-scanning technology isultrasound imaging. In this type of sensor, two transducers are placedon the x- and y-axes of a plate of glass—one each for receiving andtransmitting—for propagating ultrasound waves through a glass plate;when the finger is placed on top of the glass, the finger impedes thewaves and the receiving transducer can measure the alteration in wavepatterns. This type of scanner is very new and largely untested in avariety of conditions, but initial results show promise for thetechnology. It combines the large plate size and ease of use of theoptical scanners with the ability to pervade dirt and residue on thescanner, an advantage of capacitive scanners.

Touch Screen Technologies

Touch screens are quite similar to the fingerprint scanners describedabove. They recognize a finger pressure on the screen and typicallycalculate the center or peak point of the pressure. Current touch screentechnologies fall under five different types of technology: analogresistive, capacitive, infrared, acoustic wave, and near field imaging.The analog resistive, capacitive and acoustic wave technologies are themost commonplace due to their clarity and endurance under a variety ofconditions. Infrared is very sensitive to a light touch and may beimpractical, while near field imaging is very new, suitable for veryharsh conditions, and frequently cost-prohibitive. For these reasonsonly the first three technologies are examined in much detail. Similarlyto the fingerprint scanning technology there is typically an associatedsoftware or firmware controller to perform requisite data analysis.

The analog resistive technology is composed of a glass plate and aplastic plate stacked over a flat-panel screen or display. Both theglass and plastic plates are coated with a transparent conductivematerial, such that the conductive material is sandwiched between thetwo plates. Tiny separator dots keep the two plates from touching undernormal conditions, but when pressure is applied to the plastic plate,the dots move and the two surfaces come together to conduct electricity.An electronic controller instantly calculates the x- and y-coordinates,allowing resistive touch screen technologies to have very high precisionand resolution. This also allows an individual to have relative freedomwhen selecting an object as a stylus; the individual may use a pen,finger, or other convenient utility.

Capacitive coupled technologies require the use of a conductivestylus—this may be a finger, but not a gloved hand because the clothwill prevent the conduction of charge. Capacitive technologies use aflat-panel display with a single glass plate resting on top. The glassplate is covered in a transparent metal oxide on the exterior surface;when the finger or alternate stylus comes into contact with theconductive surface; capacitive coupling occurs at the point of contactand draws electrical current. The controller registers the change incurrent and the x- and y-coordinates can be determined. As mentionedabove, because the technology requires use of a conductive stylus,non-conductive surfaces will prevent the change in electrical currentand will not have any effect on the touch screen. Furthermore, theexposed glass surface in this technology makes it susceptible toscratches and can inhibit correct operation of the screen.

Acoustic wave touch screens are more complicated than the capacitive andresistive technologies. There are two types of acoustic wavetechnologies: guided acoustic wave (GAW) and surface acoustic wave(SAW). Both use a single plate of glass placed on top of a flat-paneldisplay, with a similar transducer arrangement as described above forthe ultrasound imaging. GAW screens transmit a wave through the glasspanel (using the glass as a waveguide), while SAW screens transmit thewave on the surface of the glass; in both technologies, transducersdetect a dampening of the wave that occurs when pressure is applied tothe glass, which is translated into x- and y-coordinates. Similarly tothe capacitive coupled screens, SAW screens have stylus limitations; thestylus must be soft and able to absorb energy in order to dampen thewave, and are generally only practical in instances where the stylus isa finger. These types of touch screens also have the glass surfacelimitation described above.

DESCRIPTION OF THE RELATED ART

A multitude of single-purpose display apparatuses, fingerprint sensorsand touch screens are available commercially. Furthermore, severalcompanies offer commercial products that embed fingerprint-scanninghardware within display apparatus technology. One such example,Ethentica and Philips FDS′ (a wholly owned subsidiary of PhilipsCorporation) joint venture TactileSense™ finger scanning hardware,comprises a transparent optical sensor that can be embedded into a paneof glass. The TactileSense optical sensor comprises a uniqueTactileSense polymer, a silicon glass camera/CCD, and a control ASIC.The TactileSense polymer is placed on top of the silicon camera, whichis embedded within glass to provide hardness and durability. TheTactileSense polymer is the heart of the sensor, comprising five layers:insulating, black-coat, transparent conductive, light-emitting phosphor,and base. The insulating and black-coat layers enhance the performanceof the sensor by preventing liquid or other particles from entering thesensor, and by preventing sunlight from entering the sensor. The chieflayers are the transparent conductive and light-emitting phosphorlayers, which serve to supply current to the polymer and to illuminatethe fingerprint. When a finger is placed on the TactileSense polymer,the polymer illuminates the fingerprint and creates an image. Thesilicon camera detects the illumination, and the ASIC converts it todigital format for processing.

U.S. Pat. No. 6,327,376 to Harkin describes a fingerprint sensorcomprised of an array of sensing elements. The sensing elements use bothcapacitive and optical techniques to generate the image; the device isconstructed using a transparent conductive material for the electrodescontained within. However, despite the inclusion of the sensor within adisplay apparatus, there is little discussion of using the display as atouch screen or user navigation interface.

U.S. Pat. No. 6,501,846 to Dickinson et al. discloses a method andsystem for computer access and cursor control using a relief objectimage generator. The relief object image generator is capable ofcapturing a 2-D image based on the 3-D relief of an object, such as afinger. The apparatus of Dickinson's invention can be used tosimultaneously authenticate an individual's fingerprint, and move acursor on a screen or perform other control-related functions related tothe movement of the individual's finger. This application is targetedprimarily at replacing mice, function keys, and other control mechanismson devices where space is limited. However, Dickinson does not addressuse of biometric recognition incorporated with touch screen usernavigation.

DigitalPersona also offers fingerprint-scanning hardware that istransparent and can be placed over display apparatuses, marketed asU.are.U Crystal™. This hardware is also comprised of an optical sensorthat uses completely transparent materials. It is ultra-thin, enablingit to be placed in mobile or other electronic devices where real estateis a significant concern. Again, however, this product does notdemonstrate any of the touch screen properties as exhibited in thecurrent invention.

BRIEF SUMMARY OF THE INVENTION

The invention disclosed herein describes a man-machine interface devicefor controlling access to electronic devices. The man-machine interfacedevice comprises an electronic display apparatus that is capable ofpresenting graphic text, images, icons, and other data typically shownon a screen, while further including a transparent finger touch sensorregion that is seated above the display apparatus. This finger touchsensor region is responsible for determining the presence and absence ofa finger, and is further responsible for generating fingerprint imageswhen a finger is detected. The man-machine interface device alsoincludes a controller unit that is coupled to the display apparatus, thefinger touch sensor region, and at least one electronic device. Thecontroller unit is capable of controlling data flow between the displayapparatus, the finger touch sensor region and the electronic device, andfor calculating finger touch locations based on a fingerprint imagegenerated by the transparent finger touch sensor region. It can receivetext from the electronic device, which is intended for presentation onthe display apparatus, or conversely send a fingerprint image to theelectronic device, among other functions.

The method of the invention describes a process for authenticatingindividuals and verifying their security privileges to access sensitivedata, based on a finger-touch selection of an icon presented on thedisplay apparatus of the man-machine interface device.

BRIEF DESCRIPTION OF DRAWINGS Master Reference Numeral List

FIG. 1: Apparatus

-   -   100 Apparatus    -   101 Finger touch sensor region    -   102 Display apparatus    -   103 Controller

FIG. 2: Apparatus, based on optical sensor technology

-   -   102 Display apparatus    -   201 Charge coupled device    -   202 Glass or plastic plate    -   203 Light source

FIG. 3: Apparatus, based on capacitive sensor technology

-   -   102 Display apparatus    -   302 Glass plate, coated with transparent metal oxide    -   303 Electric field

FIG. 4: Apparatus, based on ultrasonic/acoustic wave technology

-   -   102 Display apparatus    -   402 Glass plate    -   403 Ultrasonic/acoustic wave generator

FIG. 5: Authenticating to the apparatus

-   -   501 Human thumb    -   502 E-mail icon    -   503 PDA

FIG. 6: Method for authenticating

-   -   601 Is there a finger present?    -   602 Create a fingerprint image    -   603 Calculate the location of the finger touch    -   604 Is there an icon at the finger touch location?    -   605 Is there a function associated with the icon?    -   606 Does the function require fingerprint authentication?    -   607 Does the fingerprint match a stored fingerprint?    -   608 Determine access rights for matched fingerprint    -   609 Allow user access to function?    -   610 Authorize user access to function    -   611 Quit

FIG. 1 is a schematic view of the apparatus of the invention.

FIG. 2 is a schematic view of the apparatus of the invention, whenoptical sensing technology is used.

FIG. 3 is a schematic view of the apparatus of the invention, whencapacitive sensing technology is used.

FIG. 4 is a schematic view of the apparatus of the invention, whenultrasonic/acoustic wave technology is used.

FIG. 5 is a schematic view of the apparatus of the invention being usedto authenticate to a PDA.

FIG. 6 is a flow chart of the method of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The apparatus of the invention is a primary man-machine interface devicethat incorporates biometric authentication into a touch-sensitivedisplay. Juxtaposing these two technologies provides a simple userinterface, and additionally, an economy of space for handheld orportable devices that require ease-of-use along with biometricauthentication; devices can use the functionality of a display, controlkeys or buttons, and a fingerprint sensor, by replacing them with theman-machine interface device of this invention.

Fingerprint scanning typically requires more detail, precision, and dataanalysis then touch screen technology. The most common use offingerprint scanning is comparison between a new, “live” fingerprint,and an older stored fingerprint, where the comparison is typicallybetween minutiae points calculated for both fingerprints. This can beused to verify or identify an individual who has already been enteredinto a system. If the fingerprint scanner fails to accurately analyze aprint, the scanner may provide a false acceptance—reporting that the newfingerprint is the same as the old, when they actually are not—or falserejection—reporting that the two fingerprints are different when theyare not. However, if a touch screen registers a touch locationincorrectly, it is only a minor inconvenience to recalibrate the touchscreen and renavigate the user interface.

The primary embodiment of the man-machine interface device 100incorporates a transparent finger touch sensor region 101, an electronicdisplay apparatus 102, and a controller 103, as seen in FIG. 1. Thefinger touch sensor region 101 is layered on top of the displayapparatus 102, and is capable of determining the presence and absence offinger touches. It can additionally generate fingerprint images, whichare transmitted to, and used by, the controller 103. The displayapparatus 102 must be capable of presenting graphic data, text, images,icons and other information, and may range from a cathode ray tubedisplay, such as a television or monitor, to a liquid crystal display.The controller 103 is coupled to the finger touch sensor region 101 andthe display apparatus 102, as well as peripheral electronic devices,such as a PDA.

One alternate embodiment of the apparatus 100 is based on opticalfingerprint scanner technology, and can be seen in FIG. 2. A plate 202is placed over the display apparatus 102, with a light source 203 and aCCD 201 between the two. The light source 203, the plate 202, and theCCD 201 must all be transparent, or items would not be viewable on thedisplay apparatus 102.

FIG. 3 shows an alternate embodiment of the present invention, which isbased on a capacitive fingerprint sensor and a capacitive touch screen.A glass plate 302 coated with transparent metal oxide is placed on topof the display apparatus 102. When the finger is placed on the glassplate of the finger touch sensor region 101, an electric field 303 iscreated and the finger touch location and fingerprint can be determined.

Another alternate embodiment of the apparatus 100 is based on theultrasonic imaging fingerprint sensor and the acoustic wave touchscreen. This can be seen in FIG. 4. Again a glass panel 402 is placed onthe display apparatus 102. Ultrasonic waves 405 are propagated by meansof an ultrasonic or acoustic wave generator 403 either through or on topof the glass panel 402, using it as a wave guide. When a finger isplaced on the finger touch sensor region 101 it interferes with thetraveling wave, generating the fingerprint or touch location. Becausethe wave guide is based on the principle of total internal reflection,the angle of incidence of the propagating wave 405 must be such that itdoesn't interfere with the optical properties of the display apparatus102 behind it. This is affected by the thickness of the glass panel 402and the frequency of the propagating wave 405.

Regardless of the embodiment of the apparatus 100, the controller 103must be capable of receiving data from a peripherally-connectedelectronic device and displaying it on the display apparatus 102. Thecontroller 103 must also be able to receive fingerprint images from thefinger touch sensor region 101, and to calculate the location of fingertouch events from these images. Additionally, the controller 103 isresponsible for calculating minutiae points of a fingerprint associatedwith a finger touch on the finger touch sensor region 101. Anycalculated data, such as a location or minutiae, can be transmitted fromthe controller 103 back to the peripheral device. If required, thecontroller 103 may be capable of storing fingerprint minutiae points,and/or comparing fingerprint minutiae points. In one preferredembodiment of the invention, the location can be determined byextrapolating the center point of the finger touch on the finger touchsensor region 101. However, the algorithmic choice does not fall withinthe scope of this invention; the location can be determined by anyappropriate method.

The peripherally-connected electronic device referred to above is thedevice using the man-machine interface device. For example, if theman-machine interface device were to be used as a replacement for thetouch screen and buttons on a personal digital assistant (PDA), the PDAwould be considered the peripherally-connected electronic device. It isresponsible for sending data to the controller 103 for display on thedisplay apparatus 102, and for requesting and receiving finger touchdata. Additionally, the peripherally-connected electronic device isresponsible for maintaining the association between icons or textpictured on the display apparatus 102, and accessing rights for saidfunctions.

The method of the invention provides fingerprint authentication forfunctions represented by an icon on a display. In the primaryembodiment, the method is employed while using the man-machine interfacedevice 100 installed in a PDA, but can be used with other suitabletechnology; examples explained herein will employ both. The method isintended to replace traditional user interface and authenticationmethods. For example, the PDA may receive e-mail, which the intendedrecipient wishes to keep secure. The PDA stores a registered fingerprintfor the intended recipient that is associated with the securityprivileges of the e-mail program. Additionally, the PDA displays an iconon the display apparatus 102 that accesses the e-mail program onselection.

FIG. 5 shows an individual 501 using the man-machine interface device100 of the present invention, to touch the finger touch sensor region101 over the icon 502 displayed on the display apparatus 102 of the PDA503—in this example, the e-mail icon. As seen in the flow chart of FIG.6, the finger touch sensor region 101 detects the presence of the finger(step 601), and generates an image of the fingerprint (step 602), whichis passed to the controller 103. The controller 103 calculates thefinger touch location (step 603), and determines if there is an icondisplayed on the display apparatus 102 at that location (step 604). Ifan icon exists, the PDA determines which function is associated with theicon (step 605) and if the function requires fingerprint authentication(step 606).

If the function does not require authentication, the PDA directlyauthorizes access to the function. However, in this example with e-mail,the function does require fingerprint authentication. The PDA examinesstored fingerprints, verifying the new image against the stored images(step 607), until a match is found. If a match is found, the PDAdetermines the security privileges associated with the fingerprint (step608) and determines if the e-mail function is among these privileges(step 609). If not, the method terminates (step 611); if it is, the PDAallows access to the e-mail function (step 610), and then terminates theauthentication method (step 611).

While the description above refers to particular embodiments of thepresent invention, it will be understood that many modifications may bemade without departing from the spirit thereof. The accompanying claimsare intended to cover such modifications as would fall within the truescope and spirit of the present invention.

1. An apparatus, comprising: a memory configured to store a plurality ofbiometric templates and a plurality of security privileges, eachbiometric template from the plurality of biometric templates beingassociated with a security privilege from the plurality of securityprivileges; a touch screen configured to receive an icon selection inputat a location of the touch screen; and a processor operatively coupledto the memory and the touch screen, the processor configured to permitaccess to a function associated with the location of the touch screenwhen (1) the icon selection input is associated with a biometrictemplate from the plurality of biometric templates, and (2) a securityprivilege from the plurality of security privileges is associated withthe function and that biometric template.
 2. The apparatus of claim 2,wherein: the processor is configured to deny access to the functionassociated with the location of the touch screen when at least one of(1) the icon selection input is not associated with a biometric templatefrom the plurality of biometric templates, or (2) a security privilegefrom the plurality of security privileges is not associated the functionand that biometric template.